1 files changed, 7 insertions, 1 deletions
diff --git a/internal/world/world.go b/internal/world/world.go
index 3dfa99b..b582faf 100644
--- a/internal/world/world.go
+++ b/internal/world/world.go
@@ -37,7 +37,9 @@ func New(dataDir string) *World {
 }
 
 func (w *World) LoadRoom(id int) (*Room, error) {
+	w.mu.Lock()
 	path, ok := w.roomPathIndex[id]
+	w.mu.Unlock()
 	if !ok {
 		return nil, fmt.Errorf("read room %d: no such room", id)
 	}
@@ -119,7 +121,9 @@ func (w *World) SeedGroundItems(roomID int) {
 }
 
 func (w *World) RoomIndex() map[int]bool {
-	ids := make(map[int]bool)
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	ids := make(map[int]bool, len(w.roomPathIndex))
 	for id := range w.roomPathIndex {
 		ids[id] = true
 	}
@@ -139,6 +143,8 @@ func (w *World) AddRoomPath(id int, path string) {
 }
 
 func (w *World) GetRoomPath(id int) (string, bool) {
+	w.mu.Lock()
+	defer w.mu.Unlock()
 	path, ok := w.roomPathIndex[id]
 	return path, ok
 }